Bulletin d’avalanche

East Cabinet Mountains

Idaho Panhandle Avalanche Center
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Danger d’avalanche

Sat
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 3 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Instabilities near the surface of the snowpack remain the foremost avalanche concern. Recent snowfall and winds have created slabs of snow that will be possible to trigger in steep terrain that faces north and east. Areas just below ridgelines at elevations above 6,000' will be the most likely spots to trigger avalanches on Friday and Saturday.

Heavy mountain snow and gusty winds will enter the area Sunday through Tuesday. Anticipate avalanche danger to begin rising on Sunday afternoon.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–2

    This past Tuesday and Wednesday the area received consistent snowfall at upper elevations combined with moderate winds out of the southwest. On Friday it will be possible to trigger small wind slabs in steep terrain at elevations above 6,000' on north and east aspects. On Thursday we observed that the new snow had been scoured off of south and west aspects near ridgelines and transported into northeasterly terrain where it was packed into cohesive slabs. These slabs were cracking easily under foot while travelling below ridgelines. We also observed multiple natural avalanches that had released the day before in steep and northeast facing terrain. You can avoid this avalanche problem by steering clear of steep terrain directly below ridgelines on north and east aspects where these pockets of wind slab are patiently waiting to be triggered.

  • Loose Wet

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1

    Warm temperatures at lower elevations and periods of sunshine on Friday will cause small "loose-wet" avalanches to become an issue at lower elevations and in terrain exposed to the afternoon sun. If the snowpack surface becomes soft and slushy you can avoid potential injury by steering clear of steep terrain that is littered with obstacles such as cliffs and trees.

Avalanche Discussion

Avalanche conditions across the Kootenai have been following a consistent theme since the rains and warm temperatures formed a thick crust at the beginning of February.  The thick crust layer has bridged or eliminated deeper weak layers within the snowpack making instabilities close to the surface our primary concern. Wind slabs and loose-wet snow avalanches caused by rain and warm temperatures have been the issues for the most part.

On Thursday we travelled into the Pulpit Mountain area where we found some reactive wind slabs that were concerning enough to steer us away from entering steep and northeasterly terrain below ridgelines. These slabs will become more difficult to trigger as they gain strength under the mild temperatures Friday and Saturday but should be given some respect as they can be triggered and are just big enough to be a serious concern. We also found a layer of surface hoar buried about 8" below the surface. It doesn't have a lot of potential to be an issue as the snow above and below it is very soft. This could change as a big weather system rolls in on Sunday. For me the big concern regarding avalanche stability is the thin crust layer that can be found near the surface of our snowpack across the area. This layer will be an optimal sliding surface as it becomes buried with heavy snow beginning Sunday. As I mentioned in the "Bottom Line", our relatively stable snowpack is going to change on us Sunday with conditions expected to become dangerous as heavy snow and strong westerly winds enter the area. Sunday will be a day to dial back your terrain choices to lower angle slopes that are sheltered by Timber.

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